I've seen it stated that he died of "complications from Crohn's disease" which in my mind would include a surgery gone wrong. I had an unexpected surgery which required anesthesia during a trip abroad myself, it's likely the chances of death from the surgery or event itself were somewhere in the 0.1-1% range.

I'm otherwise young-ish and healthy, and didn't know I had Crohn's before this happened, though I've had intermittent digestive issues that I thought "weren't a big deal" through most of my adulthood. I can only imagine someone who already knew they had Crohn's had it worse than myself.